This invention relates generally to the field of consolidating metallic bodies, and more particularly to rapid and efficient and heating and handling of granular media employed in such consolidation, as well as rapid and efficient heating and handling of pre-form powdered metal bodies to be consolidated.
The technique of employing carbonaceous particulate or grain at high temperature as pressure transmitting media for producing high density metallic objects is discussed at length in U.S. Pat. Nos. 4,140,711 and 4,539,175, the disclosures of which are incorporated herein, by reference.
Major problems in such processes include efficient heating of the media to usable high temperature, and handling of the thus heated media. Past methods used to heat the pressure transmitting media involved conventional box furnaces with glo-bars or Ni-Chrome wire heating elements. At first a container was used to hold the media during heating. This container was removed from the furnace for filling and emptying. Later, methods involved a fluidized bed retort to hold the media, surrounded by silicon carbide heating elements and insulation to prevent heat loss. The fluidized bed furnace proved to be faster and more efficient than the first method but not enough to be used in an efficient and rapid manufacturing process.